function send_xmlhttprequest(state_change, method, url, content, headers) {
    var xmlhttp = (window.XMLHttpRequest ? new XMLHttpRequest() : (window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : false));
    if (!xmlhttp) {
        return false;
    }
    xmlhttp.open(method, url);
    xmlhttp.onreadystatechange = function () {
        state_change(xmlhttp);
    };
    if (headers) {
        for (var key in headers) {
            xmlhttp.setRequestHeader(key, headers[key]);
        }
    }
    xmlhttp.send(content);
    return true;
}

function nastavOpacity(op)
{
 blokFirma.style.opacity = op;
 blokFirma.style.MozOpacity = op;
 blokFirma.style.KhtmlOpacity = op;
 blokFirma.style.filter = 'alpha(opacity=' + (op * 100) + ');';
}
 
function fadeIn()
{
 nactiFirmu();
 for (i = 0; i <= 1; i += 0.01)
 {
 	setTimeout("nastavOpacity(" + i +")", i * fadeSpeed);
 }
 setTimeout("fadeOut()", (fadeSpeed + showTime));
}

function fadeOut()
{
 for (i = 0; i <= 1; i += 0.01)
 {
 	setTimeout("nastavOpacity(" + (1 - i) +")", i * fadeSpeed);
 }
 setTimeout("fadeIn()", (fadeSpeed + hiddenTime));
}

function startFirmy()
{
 blokFirma = document.getElementById('nazevFirma');
 fadeSpeed = 1000;
 hiddenTime = 500;
 showTime = 2000;
 if (blokFirma)
 {
 	fadeIn();
 }
}

function nactiFirmu()
{
	setTimeout(function () {
		send_xmlhttprequest(function (xmlhttp) {
			if (xmlhttp.readyState == 4) {
				if (xmlhttp.responseText != 'error')
				{
				 blokFirma.innerHTML = xmlhttp.responseText;
				}
				else
				{
				 blokFirma.innerHTML = "chyba";
				}
			}
		}, 'GET', '_firmy.php');
	}, 1);
}